Conical refraction, for annular pumping of an efficient vortex Nd:YAG laser

We presented a proof-of-concept investigation upon an end-pumped and vortex Nd:YAG laser. In this laser, for the first time, the conical refraction (CR) ring of a biaxial KGd(WO4)(2) crystal was used for annular pumping. Owing to nearly 100% conversion efficiency in forming the CR ring, the Nd: YAG laser was highly efficient and emitted LG(01)-mode vortex light with 177.5 mW beam power and 65% slope efficiency. This study showed the CR ring pumping would favor the production of a compact, simple and efficient vortex laser. It is expected that, in future, the CR ring pumping technique would also facilitate the high-power vortex solid-state laser where a long gain medium is required.